Архивы Performance

Configuring Cloudflare’s CF-Connecting-IP Header

Since when Cloudflare proxy is enabled, requests to the web server will come from Cloudflare servers, and not directly from users, you need to configure the CF-Connecting-IP header, which transmits the user’s real IP address. After configuration, it will be displayed as before in logs and requests.

Logging Deadlocks InnoDB

Once I needed to detect Deadlocks and log them, I will describe how to do it:

Solution for heavy CPU load MikroTik CRS106-1C-5S

One day I was asked to look at MikroTik CRS106-1C-5S, whose users could not use the Internet normally, there was no speed and ping requests dropped out. When I looked at CPU utilization, it was almost 100% (in the menu System – Resources).

iPerf Mulicast

I will show an example of running iPerf to test network bandwidth using UDP Multicast.

Zabbix. Upgrading the database to primary keys

Starting with Zabbix 6.0, primary keys are used for all tables in new installations, but since I upgraded Zabbix server to version 6.4, I had to manually update the tables after the upgrade.

Before updating, first of all, open the menu “Report” – “System Information” and make sure that the keys are not used, this will be indicated by the entry – “Database history tables use primary key – No”, if the keys are used, then this entry simply will not be.

Messages net_ratelimit: X callbacks suppressed

Once I found the following messages in the dmesg log:

Script to bind Intel NIC interrupts to processor cores

I will give the script code from Intel to bind interrupts of Intel network adapters to processor cores, and also show examples of its use:

Taskset – bind process to CPU cores

By default, processes use all the processor cores, but sometimes it is necessary to release the 0 core, which is usually the most loaded, or assign some processes only to the second CPU, etc., in this case, taskset will help.

Increase the port range net.ipv4.ip_local_port_range

There is a possibility that on a highly loaded server, such as a proxy or router, with a very large number of connections, free ports in the allocated range may run out, so you need to look at the current number used and, if necessary, increase the net.ipv4.ip_local_port_range value.

Configuring logrotate to rotate logs

Logrotate is used to control the logging system, compress log files, delete old ones, etc.
The configuration is located at /etc/logrotate.d/ and /etc/logrotate.conf.